I found the text and the reader responses quite interesting and so analyzed the text of the letter using corpus linguistic methodologies.

Using Sketch Engine tools, I looked at keywords:

Considering the topic of the letter, the themes of the keywords are not unexpected, however our is a word of interest, as it is often used to frame the in-group.

When the concordance lines are searched, it can be seen that a discourse related to the material cost of war and armed conflict is present. Another discourse is related to the the construction of what defines being British: our country, our values, our way of life, our history. It is interesting that the Prime Minister should use discursive strategies related to the defense of the material cost of war in relation to the defense of the ‘British way of life’ in order to argue the validity of entering into an armed conflict on foreign soil.